Single-shift Worker Allocation Using Two-phase Goal Programming

In this paper, we present a single-shift workforce planning tool: the Head Count Allocation Solver (HCA) for a high volume manufacturing facility with several machine groups at each operation. Each machine group at a given operation requires a number of workers with specified skill levels and qualifications, and each qualified worker has a preference for operations and machine groups based on his/her allocations in the prior shifts. The workforce planning problem is formulated and solved using a two-phase goal programming approach. In the first phase, the model allocates the workers to machine groups and identifies the shortage of workers (referred to as a gap) with certain skill levels and qualification for all machine groups at each operation. If there exists a gap at any machine group, then, in the second phase, corresponding skill level constraints are relaxed and the workers are reallocated to the machine groups in order to minimize the gap. The goal programming model considers real-world manufacturing issues such as partial allocation and historical worker-machine group. The final allocation report provides the worker-machine group allocations, gap in skill-levels at machine groups, and the list of unallocated workers that aid in identifying the set of workers and operational stages while designing effective cross-training programs. The results from this research have successfully been tested and validated in a real manufacturing environment with a potential for savings costs due to optimal allocation of workers to machine groups and cross-training programs.